Locking apparatus for parking brake

ABSTRACT

A locking apparatus for a parking brake includes a parking lever, a parking lever spring applying a restoring force to the parking lever, a cylinder of which an oil hole is formed thereto, a piston comprising a piston rod connected to the parking lever and a piston main body disposed within the cylinder, and the piston movable along length direction of the cylinder according to supplying or releasing of oil through the oil hole, a solenoid valve and a locking unit disposed within the cylinder for unlocking the piston when the solenoid valve is supplied electric power and for locking the piston when the solenoid valve is not supplied electric power.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2011-0072554 filed Jul. 21, 2011, the entire contentsof which application is incorporated herein for all purposes by thisreference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a locking apparatus for a parkingbrake. More particularly, the present invention relates to a lockingapparatus for a parking brake which may maintain locking state evenelectric power is not applied.

2. Description of Related Art

Generally, a parking apparatus (parking brake), which maintains avehicle in stop state by locking a sprag disposed to an output shaftwith a parking gear at parking range “P”, is provided to an automatictransmission.

FIG. 4 is a cross-sectional view of a conventional parking brake.

A conventional parking apparatus includes a detent lever 12 which isconnected to a shift lever 10 and rotates according to the shift lever10 selecting parking mode, a parking rod 14 which is connected to thedetent lever 12 and moves rectilinearly by rotating of the detent lever12 and of which a roller 28 is disposed to an end thereof, a sprag 18which is rotatable around a hinge 30 and of which a locking protrusion34 is formed to an end thereof, a return spring 32 which is disposed tothe hinge 30 for supplying a restoring force to the sprag 18 and aparking gear 22 of which an engaging groove 20 selectively engaged withthe locking protrusion 34 is formed thereto.

A rod spring 26 is disposed to the parking rod 14 for supplying arestoring force thereto.

In the conventional parking apparatus, when a driver manipulates theshift lever 10 to a parking mode, the detent lever 12 connected to theshift lever 10 rotates and then the parking rod 14 connected to thedetent lever 12 moves rectilinearly. And then the roller 28 connected toan end of the parking rod 14 rotates the sprag 18.

And thus the parking gear 22 of the sprag 18 is engaged with theengaging groove 20 of the parking gear 22 for fixing the parking gear22, so that parked state is maintained.

When the shift lever 10 is shifted from parking mode to other mode, theparking rod 14 cranks back by elastic force of the rod spring 26 and thesprag 18 also cranks back by elastic force of the return spring 32 andthus the locking protrusion 34 and the engaging groove 20 are separatedso that parked state is finished.

Recently, a SBW (Shift By Wire) is usually used for transmittingdriver's will to TCU so that mechanical parking is released by hydraulicpressure. So that just small power comparing to a conventional TGS(Transmission Gear Shift) lever (P/R/N/D) is required, and thus a driveris provided convenience.

Also, a solenoid valve and locking apparatus are used for preventingmechanical parking of a transmission when a vehicle is driven as adriving mode, for example D shift, and hydraulic pressure supplied to aparking piston is rapidly released.

However, in the conventional art, electric current must be supplied formaintaining locking state. And thus, if electric power in N shift is cutoff, a brake is engaged.

With this scheme, a driver is provided with an inconvenience especiallyin a narrow parking area.

The information disclosed in this Background section is only forenhancement of understanding of the general background of the inventionand should not be taken as an acknowledgement or any form of suggestionthat this information forms the prior art already known to a personskilled in the art.

SUMMARY OF INVENTION

Various aspects of the present invention provide for a locking apparatusfor a parking brake having advantages of maintaining shift mode even inan engine-off state.

The present invention has been made in an effort to provide a lockingapparatus for a parking brake having advantages of maintaining shiftmode even in an engine-off state without supplying electric power anddischarging a battery.

A locking apparatus for a parking brake according to various aspects ofthe present invention may include a parking lever, a parking leverspring applying a restoring force to the parking lever, a cylinder ofwhich an oil hole is formed thereto, a piston comprising a piston rodconnected to the parking lever and a piston main body disposed withinthe cylinder, and the piston movable along length direction of thecylinder according to supplying or releasing of oil through the oilhole, a solenoid valve and a locking unit disposed within the cylinderfor locking the piston when the solenoid valve is supplied with electricpower and for locking the piston when the solenoid valve is not suppliedwith electric power.

The locking unit may include a control rod which is selectively movablealong length direction of the cylinder according to the electric powersupplied to the solenoid valve and the control rod of which a slantportion is formed thereto, a control portion which is rotatable around ahinge and disposed within the cylinder and the control portion of whicha protrusion is formed to an end of which, a plate formed to an end ofthe control rod, a seat movably disposed to the control rod andcontacting the control portion and a seat spring disposed between theplate and the seat for supplying a restoring force to the seat, whereina stepped portion is formed to the piston main body for the protrusionto be selectively locked thereto.

The slant portion may push the other end of the control portion, thecontrol portion may rotate around the hinge and the locking of theprotrusion and the stepped portion may be released when the solenoidvalve is supplied with the electric power.

The control portion may rotate around the hinge by restoring force ofthe seat spring and the protrusion and the stepped portion may be lockedwhen the electric power supplied to the solenoid valve is cut off.

The locking apparatus may further include a plunger which is connectedto the control rod for moving the control rod along length direction ofthe piston when the solenoid valve is supplied with the electric powerand a plunger spring supplying a restoring force to the plunger for theplunger to be moved when the electric power supplied to the solenoidvalve is cut off.

The locking apparatus may further include a rod guider which guides thecontrol rod and supports the plunger spring.

The locking apparatus may further include a finger stop which isdisposed to the piston rod for limiting movement of the piston rod.

The locking apparatus may further include a seat guider which isdisposed within the cylinder for guiding the seat.

A locking apparatus for a parking brake according to various aspects ofthe present invention may include a parking lever, a parking leverspring applying a restoring force to the parking lever, a cylinder ofwhich an oil hole is formed thereto, a piston comprising a piston rodconnected to the parking lever and a piston main body disposed withinthe cylinder and a stepped portion is formed thereto, and the pistonmovable along length direction of the cylinder according to supplying orreleasing of oil through the oil hole, a solenoid valve, a plungermovable along length direction of the piston when the solenoid valve issupplied with the electric power, a plunger spring supplying a restoringforce to the plunger for the plunger to be moved when the electric powersupplied to the solenoid valve is cut off, a rod guider supporting theplunger spring and a locking unit disposed within the cylinder forlocking the piston when the solenoid valve is supplied with electricpower, wherein the locking unit may include a control rod which isselectively movable with the plunger along length direction of thecylinder, being guided by the rod guider, according to the electricpower supplied to the solenoid valve and the control rod of which aslant portion is formed thereto, a control portion which is rotatablearound a hinge and disposed within the cylinder and the control portionof which a protrusion is formed to an end of which, a plate formed to anend of the control rod, a seat movably disposed to the control rod andcontacting the control portion and a seat spring disposed between theplate and the seat for supplying a restoring force to the seat.

The slant portion may push the other end of the control portion, thecontrol portion may rotate around the hinge and the locking of theprotrusion and the stepped portion may be released when the solenoidvalve is supplied with the electric power.

The control portion may rotate around the hinge by restoring force ofthe seat spring and the protrusion and the stepped portion may be lockedwhen the electric power supplied to the solenoid valve is cut off.

The locking apparatus may further include a finger stop which isdisposed to the piston rod for limiting movement of the piston rod.

The locking apparatus may further include a seat guider which isdisposed within the cylinder for guiding the seat.

According to various aspects of the present invention, shift mode may bemaintained even in an engine-off state without supplying electric powerand discharging a battery.

And even an engine operation is stopped in N shift, the N shift mode maybe maintained and thus a vehicle may be easily parked in a narrowparking area.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an exemplary locking apparatus for aparking brake according to the present invention operating in R/N/Dshift mode.

FIG. 2 is a cross-sectional view of an exemplary locking apparatus for aparking brake according to the present invention operating in P shiftmode.

FIG. 3 is an enlarged view of A of FIG. 1.

FIG. 4 is a cross-sectional view of a conventional parking brake.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

For easy comprehension, constituent elements which are described indescription of the related art will be described using the samereference numeral.

FIG. 1 is a cross-sectional view of a locking apparatus for a parkingbrake according to various embodiments of the present inventionoperating in R/N/D shift mode and FIG. 2 is a cross-sectional view of alocking apparatus for a parking brake according to various embodimentsof the present invention operating in P shift mode.

Referring to FIG. 1 and FIG. 2, a locking apparatus for a parking brakeaccording to various embodiments of the present invention includes aparking lever 110, a parking lever spring 100 applying a restoring forceto the parking lever 110, a cylinder 300 of which an oil hole 310 isformed thereto, a piston 200 including a piston rod 210 connected to theparking lever 110 and a piston main body 240 disposed within thecylinder 300, and the piston 200 movable along length direction of thecylinder 300 according to supplying or releasing of oil 151 through theoil hole 310, a solenoid valve 600 and a locking unit 400 disposedwithin the cylinder 300 for locking the piston 200 when the solenoidvalve 600 is supplied with electric power and for locking the piston 200when the solenoid valve 600 is not supplied with electric power.

The locking unit 400 includes a control rod 410 which is selectivelymovable along length direction of the cylinder 300 according to theelectric power supplied to the solenoid valve 600 and the control rod410 of which a slant portion 415 is formed thereto, a control portion420 which is rotatable around a hinge 430 and disposed within thecylinder 300 wherein the control portion 420 includes a protrusion 440formed to an end thereof, a plate 412 formed to an end of the controlrod 410, a seat 450 movably disposed to the control rod 410 andcontacting the control portion 420 and a seat spring 414 disposedbetween the plate 412 and the seat 450 for supplying a restoring forceto the seat 450.

A stepped portion 250 is formed to the piston main body 240 for theprotrusion 440 to be selectively locked thereto.

The locking apparatus further include a plunger 550 which is connectedto the control rod 410 for moving the control rod 410 along lengthdirection of the piston 200 when the solenoid valve 600 is supplied withthe electric power and a plunger spring 555 supplying a restoring forceto the plunger 550 for the plunger 550 to be moved when the electricpower supplied to the solenoid valve 600 is cut off.

The locking apparatus further includes a rod guider 500 which guides thecontrol rod 410 and supports the plunger spring 555.

When the solenoid valve 600 is supplied with electric power, magneticforce generated by a coil 610 pushes the plunger 550 and thus thecontrol rod 410 moves to leftward of FIG. 1.

On the contrary, when supplied with electric power to the solenoid valve600 is cut off, the control rod 410 moves to rightward of FIG. 1 by therestoring force of the plunger spring 555.

The locking apparatus further includes a finger stop 220 which isdisposed to the piston rod 210 for limiting movement of the piston rod210.

The locking apparatus further includes a seat guider 455 which isdisposed within the cylinder 300 for guiding the seat 450.

When the solenoid valve 600 is supplied with power, the slant portion415 pushes the other end of the control portion 420, the control portion420 rotates around the hinge 430, and locking of the protrusion 440 andthe stepped portion 250 is released.

When the power supplied to the solenoid valve 600 is cut off, thecontrol portion 420 rotates around the hinge 430 by the restoring forceof the seat spring 414 and thus the protrusion 440 and the steppedportion 250 are locked.

In various embodiments of the present invention, releasing of thelocking denotes a state that the piston 200 is in movable state withoutlocking with the locking unit 400.

Also, the locking state means a state that the piston 200 is inunmovable state by locking with the locking unit 400.

Hereinafter, parking mode means a state that the oil 151 within thecylinder 300 is released as shown in FIG. 2 and others mode (except theparking mode) means a state that the oil 151 is supplied to within thecylinder 300 and the piston 200 moves to rightward as shown in FIG. 1.

According to rotation of the parking lever 110, a sprag 18 and a parkinggear 22 shown in FIG. 4 are engaged in the parking mode and theengagement are released in the others mode.

Construction of the parking lever and the sprag 18 and so on are obviousto a person skilled in the art and thus detailed description will beomitted.

Hereinafter, operation of the locking apparatus for a parking brakeaccording to various embodiments of the present invention will bedescribed.

The others mode, for example, in R/N/D shift mode, will be describedreferring to FIG. 1.

In the other modes, the oil 151 is supplied to the cylinder 300 throughthe oil supply hole 310 and the piston 200 relatively moves into thecylinder 300 and the engagement of the sprag 18 and parking gear 22 isreleased (referring to FIG. 4).

The solenoid valve 600 is not supplied with power and the seat 450pushes the end of the control portion 420 by the elastic force of theseat spring 414 and thus the protrusion 440 is locked to the steppedportion 250.

That is, it is locked by the locking unit 400.

In this condition, for example, vehicle is in driving in D shift mode,even if the oil 151 is released, the parking brake (the parking system)does not operated due to connection of the protrusion 440 and thestepped portion 250.

Also, for example, even if ignition of a vehicle is off in N shift mode,the parking brake is not operated by the connection of the protrusion440 and the stepped portion 250.

The solenoid valve 600 according to various embodiments of the presentinvention is NH (normal high) type and thus even though current supplyis cut off, a state as shown in FIG. 1 may be maintained. And thus, thelocking state may be maintained and thus the neutral mode may bemaintained even in ignition off of a vehicle.

That is, in the other modes, particularly in the N shift mode, while thehydraulic pressure is released and the piston 200 may be moved towardthe spring 100 by the restoring force of the spring 100, however thestepped portion 250 is locked to the protrusion 440 and thus the piston200 may not be moved.

Is this case, the ignition is off, and thus the power supplied to thesolenoid valve 600 is cut off. And to conclude, even if an engine is offin the N shift mode, the N shift mode may be maintained.

The locking apparatus for a parking brake according to variousembodiments of the present invention may maintain current shift mode indisoperation condition without supplying power to a solenoid valve andthus discharging of a battery may be prevented.

Hereinafter, referring to FIG. 2, the operation of the locking apparatusfor a parking brake according various embodiments of the presentinvention in the parking (P) mode will be described.

In the parking mode according to various embodiments of the presentinvention, the solenoid valve 600 is supplied with current (electricpower) so that the locking state is released.

When the solenoid valve 600 is supplied with the current, as shown inFIG. 2, the plunger 550 and the control rod 410 move to the leftward ofthe drawing. The slant portion 415 pushes the other end of the controlportion 420 and the control portion 420 rotates around the hinge 430 sothat the locking (connection) of the protrusion 440 and the steppedportion 250 is released.

That is, as shown “B” of FIG. 2, the locking of the locking unit 400 isreleased and then the parking mode is implemented.

Simultaneously, the oil 151 is released through the oil hole 310 and thepiston 200 move to the leftward of the drawing by the restoring force ofthe parking lever spring 100.

And then, the sprag 18 and the parking gear 22 (referring to FIG. 4) areengaged so that the parking mode is implemented.

And then, if the vehicle mode is changed from the parking mode to theother modes, for example, to R/N/D shift modes, as shown in FIG. 1, theoil 151 is supplied through the oil hole 310, the piston 200 moves tothe rightward of the drawing, the current supplied to the solenoid valve600 is cut off and the plunger 550 and the control rod 410 move to therightward of the drawing by the restoring force of the plunger spring555.

And the seat 450 pushes the end of the control portion 420 by theelastic force of the seat spring 414, and the protrusion 440 is lockedto the stepped portion 250 so that the locking by the locking unit 400is realized.

The locking apparatus for a parking brake according to variousembodiments of the present invention may maintain current shift mode indisoperation condition without supplying power to the solenoid valve 600and thus discharging of a battery may be prevented, especially in the Nshift mode.

Also, even if the hydraulic pressure supplied to the cylinder is reducedin driving condition, the locking condition may be maintained, so thatthe parking brake is not operated and thus accident may be prevented andenergy efficiency may be enhanced.

For convenience in explanation and accurate definition in the appendedclaims, the terms left or right, and etc. are used to describe featuresof the exemplary embodiments with reference to the positions of suchfeatures as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A locking apparatus for a parking brakecomprising: a parking lever; a parking lever spring applying a restoringforce to the parking lever; a cylinder including an oil hole formedtherein; a piston comprising a piston rod connected to the parking leverand a piston main body disposed within the cylinder, and the pistonmovable along a length direction of the cylinder according to supplyingor releasing of oil through the oil hole; a solenoid valve; and alocking unit disposed within the cylinder for unlocking the piston whenthe solenoid valve is supplied with electric power and for locking thepiston when the solenoid valve is not supplied with electric power;wherein the locking unit comprises: a control rod selectively movablealong the length direction of the cylinder according to the electricpower supplied to the solenoid valve and the control rod including aslant portion is formed therein; a control portion rotatable around ahinge and disposed within the cylinder and the control portion includinga protrusion is formed on an end thereof; a plate formed to an end ofthe control rod; a seat movably disposed on the control rod andcontacting the control portion; and a seat spring disposed between theplate and the seat for supplying a restoring force to the seat, whereina stepped portion is formed to the piston main body for the protrusionto be selectively locked thereto.
 2. The locking apparatus of claim 1,wherein the slant portion pushes the other end of the control portion,the control portion rotates around the hinge and the locking of theprotrusion and the stepped portion is released when the solenoid valveis supplied with the electric power.
 3. The locking apparatus of claim1, wherein the control portion rotates around the hinge by restoringforce of the seat spring and the protrusion and the stepped portion arelocked when the electric power supplied to the solenoid valve is cutoff.
 4. The locking apparatus of claim 1, wherein the locking apparatusfurther comprises: a plunger connected to the control rod for moving thecontrol rod along the length direction of the piston when the solenoidvalve is supplied with the electric power; and a plunger springsupplying a restoring force to the plunger for the plunger to be movedwhen the electric power supplied to the solenoid valve is cut off. 5.The locking apparatus of claim 4, wherein the locking apparatus furthercomprises a rod guider that guides the control rod and supports theplunger spring.
 6. The locking apparatus of claim 1, wherein the lockingapparatus further comprises a finger stop disposed at the piston rod forlimiting movement of the piston rod.
 7. The locking apparatus of claim1, wherein the locking apparatus further comprises a seat guiderdisposed within the cylinder for guiding the seat.
 8. A lockingapparatus for a parking brake comprising: a parking lever; a parkinglever spring applying a restoring force to the parking lever; a cylinderincluding an oil hole is formed therein; a piston comprising a pistonrod connected to the parking lever and a piston main body disposedwithin the cylinder and a stepped portion is formed thereto, and thepiston movable along a length direction of the cylinder according tosupplying or releasing of oil through the oil hole; a solenoid valve; aplunger movable along the length direction of the piston when thesolenoid valve is supplied with the electric power; a plunger springsupplying a restoring force to the plunger for the plunger to be movedwhen the electric power supplied to the solenoid valve is cut off; a rodguider supporting the plunger spring; and a locking unit disposed withinthe cylinder for unlocking the piston when the solenoid valve issupplied with electric power, wherein the locking unit comprises acontrol rod selectively movable with the plunger along the lengthdirection of the cylinder, being guided by the rod guider, according tothe electric power supplied to the solenoid valve and the control rodincluding a slant portion is formed thereon; a control portion rotatablearound a hinge and disposed within the cylinder and the control portionincluding a protrusion formed to an end thereof; a plate formed to anend of the control rod; a seat movably disposed to the control rod andcontacting the control portion; and a seat spring disposed between theplate and the seat for supplying a restoring force to the seat.
 9. Thelocking apparatus of claim 8, wherein the slant portion pushes the otherend of the control portion, the control portion rotates around the hingeand the locking of the protrusion and the stepped portion is releasedwhen the solenoid valve is supplied with the electric power.
 10. Thelocking apparatus of claim 8, wherein the control portion rotates aroundthe hinge by restoring force of the seat spring and the protrusion andthe stepped portion are locked when the electric power supplied to thesolenoid valve is cut off.
 11. The locking apparatus of claim 8, whereinthe locking apparatus further comprises a finger stop disposed at thepiston rod for limiting movement of the piston rod.
 12. The lockingapparatus of claim 8, wherein the locking apparatus further comprises aseat guider disposed within the cylinder for guiding the seat.